What does it mean to be a “Jewish Muslim Atheist Christian?” After interviewing Samir Selmanovic, I’m still not sure—except that it must be a good thing on some level, since Selmanovic radiates joy, compassion, and humor.

Mr. Selmanovic’s thesis in “It’s All About God” is that when religions turn into “God Management Systems” pretending to own God, they turn into idolatry. The quest to find God beyond the boundaries of one’s faith, he argues, has to be moved from occasional conferences resembling interfaith prom parties (“That was really nice. Let’s interfaith again next year.”) to something central.